• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2237-2250
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• 2021

The analog-based Ex-core Neutron Flux Monitoring System (ENFMS) in Korean Nuclear Power Plants (NPPs) has been performing its intended functions successfully for a long time. On the other hand, the primary concern with the extended use of analog systems is the aging effect, such as mechanical failures, environmental degradation, and obsolescence. The transition to a digital-based Man-Machine Interface Systems (MMIS) in Korea and other countries has been accelerating, but some systems are still analog-based IC systems, such as the ENFMS in APR1400 NPPs. Digitalized ENFMS can become a reality using computers and microprocessors owing to the progress in digital electronics and information technology. This paper presents the result of the first phase of the research on the digitalization of the ENFMS signal processing electronics for NPPs operated or produced in Korea. It has two main parts: (1) review engineering bases of ex-core neutron flux monitoring system, including nuclear engineering, instrumentation techniques, and analog and digital signal processing techniques, and (2) analysis of analog signal processing electronics of ENFMS for OPR1000 and APR1400 power plants. They are prerequisite to the second phase of the research which is the detailed implementation of the digitalization.

• Journal of Broadcast Engineering
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• v.9 no.4 s.25
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• pp.357-370
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• 2004

In this paper we propose Digital Signal Processing (DSP) techniques for the Equalization Digital On-Channel Repeater(EDOCR) in the ATSC digital TV (DTV) System. DSP techniques consist of demodulation. baseband equalization, and remodulation. Since the time delay caused by signal processing in the EDOCR can seriously affect the performance of ATSC legacy receivers, it is required that the processing time should be minimized as much as possible. To achieve this goal, we focus on the reduction of the EDOCR's time delay with the minimization of its performance degradation. In addition, we present recommended proper parameters for hardware implementation based on extensive simulation result.

• The KIPS Transactions:PartD
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• v.19D no.3
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• pp.211-220
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• 2012

Recently K-Pop gained worldwide sensational popularity, no longer limited to the domestic pop music scene. One of the main causes can be that K-Pop mostly are "Hook Song" which has the "hook effect": a certain melody or/and rhythm is repeated up to 70 times in one song so that it hooks the ear of the listener. Also, visual effects by K-Pop dance group are supposed to contribute to gaining the popularity. In this paper, we propose a method which traces the changes of preference for Korean pop music according to the passing of time and investigates the causes using acoustic signal analysis. For this, experiments in acoustic signal analysis are performed on Korean pop music of from popular female singers in 1960s to those as of this date. Experimental results by applying acoustic signal processing techniques show that the periods discrimination is possible based on scientific evidences. Also, quantitative, objective and numerical data based on acoustic signal processing techniques are extracted compared with the pre-existing methods such as subjective and statistical data.

• Smart Structures and Systems
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• v.1 no.2
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• pp.185-215
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• 2005

Advanced signal processing techniques have been long introduced and widely used in structural health monitoring (SHM) and nondestructive evaluation (NDE). In our research, we applied several signal processing approaches for our embedded ultrasonic structural radar (EUSR) system to obtain improved damage detection results. The EUSR algorithm was developed to detect defects within a large area of a thin-plate specimen using a piezoelectric wafer active sensor (PWAS) array. In the EUSR, the discrete wavelet transform (DWT) was first applied for signal de-noising. Secondly, after constructing the EUSR data, the short-time Fourier transform (STFT) and continuous wavelet transform (CWT) were used for the time-frequency analysis. Then the results were compared thereafter. We eventually chose continuous wavelet transform to filter out from the original signal the component with the excitation signal's frequency. Third, cross correlation method and Hilbert transform were applied to A-scan signals to extract the time of flight (TOF) of the wave packets from the crack. Finally, the Hilbert transform was again applied to the EUSR data to extract the envelopes for final inspection result visualization. The EUSR system was implemented in LabVIEW. Several laboratory experiments have been conducted and have verified that, with the advanced signal processing approaches, the EUSR has enhanced damage detection ability.

• 전기의세계
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• v.29 no.9
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• pp.584-593
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• 1980

Conventional radar antenna systems are susceptible to performance degradation caused by unwanted signals received via the antenna sidelobes and/or mainlobes. Adaptive array systems offer possible solution to this interference problem by automatically steering nulls to unwanted signals providing significant system performance improvement. Another important andvantage of the adaptive array is its self-optimization capability which uses the collective incoming noise data for the nulling purposes. This paper provides a tutorial introduction to adaptive arrays as well as some new development of recent research in this area. Optimum link between the antenna theory and signal processing has been sought by illustrating the gain patterns and output signal-to-noise ratio. Signal acqusition methods are shown including a new attempt of the use of spread-spectrum techniques in conjuction with array systems.

• Journal of the Korean Society for Nondestructive Testing
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• v.16 no.1
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• pp.1-9
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• 1996

Many signal-processing techniques have been found to be useful in ultrasonic and nondestructive evaluation. Among the most popular techniques are signal averaging, spatial compounding, matched filters and homomorphic processing. One of the significant new process is split-spectrum processing(SSP), which can be equally useful in signal-to-noise ratio(SNR) improvement and grain characterization in several specimens. The purpose of this paper is to explore the utility of SSP in ultrasonic NDE. A wide variety of engineering problems are reviewed, and suggestions for implementation of the technique are provided. SSP uses the frequency-dependent response of the interfering coherent noise produced by unresolvable scatters in the resolution range cell of a transducer. It is implemented by splitting the frequency spectrum of the received signal by using gaussian bandpass filter. The theoretical basis for the potential of SSP for grain characterization in SUS 304 material is discussed, and some experimental evidence for the feasibility of the approach is presented. Results of SNR enhancement in signals obtained from real four samples of SUS 304. The influence of various processing parameters on the performance of the processing technique is also discussed. The minimization algorithm, which provides an excellent SNR enhancement when used either in conjunction with other SSP algorithms like polarity-check or by itself, is also presented.

• Journal of Information Processing Systems
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• v.15 no.5
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• pp.1068-1081
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• 2019

Signal complexity is one point of view to analyze the biological signal. It arises as a result of the physiological signal produced by biological systems. Signal complexity can be used as a method in extracting the feature for a biological signal to differentiate a pathological signal from a normal signal. In this research, Hjorth descriptors, one of the signal complexity measurement techniques, were measured on signal sub-band as the features for lung sounds classification. Lung sound signal was decomposed using two wavelet analyses: discrete wavelet transform (DWT) and wavelet packet decomposition (WPD). Meanwhile, multi-layer perceptron and N-fold cross-validation were used in the classification stage. Using DWT, the highest accuracy was obtained at 97.98%, while using WPD, the highest one was found at 98.99%. This result was found better than the multi-scale Hjorth descriptor as in previous studies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.886-900
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• 2015

Small cells are deployed in Heterogeneous Networks (HetNet) to improve overall performance. These access points can provide high-rate mobile services at hotspots to users. In a Small Cell Network (SCN), the good deployment of small cells can guarantee the performance of users on the basis of average and cell edge spectrum efficiency. In this paper, the performance of small cell deployment is analyzed by using system-level simulations. The positions of small cells can be adjusted according to the deployment radius and angle. Moreover, different Inter-Cell Interference Coordination (ICIC) techniques are also studied, which can be implemented either in time domain or in frequency domain. The network performances are evaluated under different ICIC techniques when the locations of Small evolved Nodes (SeNBs) vary. Simulation results show that the average throughput and cell edge throughput can be greatly improved when small cells are properly deployed with the certain deployment radius and angle. Meanwhile, how to optimally configure the parameters to achieve the potential of the deployment is discussed when applying different ICIC techniques.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.27-30
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• 2003

In this paper a new approach of digitalized ‘Takbon’ is introduced. By image signal processing, the letters which were written on stones can be deciphered. Epigraphic letter is detected by digital image device, digital camera. The two dimensional digital image is preprocessed because of sensor noise and detective turbulence. Color image is transformed into grey level. The letter image is analyzed in time/frequency domain. By the resultant analysis data decisive functions are calculated. Signal Processing techniques, such as scaling, clipping, digital negative, high/low filter, morphology and so on, provide algorithms that can extract letter from stones.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1438-1446
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• 1996

Infrared seekers using reticles with a single detector have been widely used due to small size and low cost. However, the analysis of the error signals and the performance in multiple targets are performed either simplistically or not at all. In this paper, we present detector signals and processing results using image and signal processing techniques, especially performance analysis in multiple targets. The simulation results are essential to make the advanced signal processing part of retical seekers which can deal with various engagement scenarios.